A staircase of 9 steps, with a standard rise and run and with railings on both sides, was used. Participants were asked to climb the staircase as quickly and as safely as possible without running or jogging. Once they reached the top of the staircase, they were asked to descend the stairs as quickly and safely as possible. For both ascent and descent, participants were advised they could use the handrails. A stopwatch was used to record the time for each ascent and descent trial separately. Time was started when the participant’s lead foot left the ground, and time was stopped when both feet were planted firmly on the final step. Both of the ascent and descent tasks were completed 2 times. The average time (in seconds) for each of stair ascent and stair descent was recorded to the nearest tenth of a second. The second dependent variable was the 6MWT. The 6MWT is a mobility and submaximal exercise test used in clinical populations.15 The 6MWT produces valid data in the assessment of both pain and physical function in people with knee OA.16 For this test, participants were instructed to walk at a self-selected pace with the aim of covering as much distance as possible in 6 minutes. Participants were allowed to slow down, stop, or sit but were reminded that the time would continue running. Verbal encouragement was provided at 1-minute intervals throughout the test in accordance with the 6MWT guidelines. 17 The 6MWT score was the distance walked to the nearest tenth of a meter.